Vacuum arc spectroscopy diagnosis and particle distribution study in the near-cathode/near anode region

The arc plasma microscopic particle distribution near cathode or anode region is experimentally investigated based on the emission spectroscopy diagnosis method in this paper. The contacts material is CuCr50 and the peak value of arc current is range from 2 kA to 6 kA. The arc images were recorded by a high-speed CCD camera, and the axial distribution of the characteristic spectral lines of microscopic particles between the arc gaps was obtained by a spectrometer and ICCD. It was found that in the low-current vacuum arc mode, the characteristic spectral lines of copper atom Cu I, chromium atom Cr I and Cu
⁺
ion Cu II were mainly distributed between the arc gaps, and few or only a few Cu
²⁺
ion Cu III spectral lines were detected in the visible range. As the arc current increases, the intensity of each spectral line as well as Cu III spectral lines increases. In order to obtain the microscopic particle transportation characteristics of the whole arc-burning process of vacuum arc, the variation pattern of Cu I and Cu II characteristic spectral lines during the whole arc-burning process was obtained by the combination of a spectrometer and a high-speed CCD camera. It was found that with an increase of arc current, the intensity of both Cu I and Cu II spectral lines at near-cathode region increases gradually, but the Cu II spectral line increases slightly at near-anode region. We can infer that even if there is a relatively high vapor density near the anode, it is not enough to ionize the copper atoms due to the reduced energy for the particles reaching the anode area.